In this study we evaluated the predictive validity of conceptual scoring. Two independent samples of Spanish-speaking language minority preschoolers (Sample 1: N = 96, mean age = 54·51 months, 54·3% male; Sample 2: N = 116, mean age = 60·70 months, 56·0% male) completed measures of receptive, expressive, and definitional vocabulary in their first (L1) and second (L2) languages at two time points approximately 9–12 months apart. We examined whether unique L1 and L2 vocabulary at time 1 predicted later L2 and L1 vocabulary, respectively. Results indicated that unique L1 vocabulary did not predict later L2 vocabulary after controlling for initial L2 vocabulary. An identical pattern of results emerged for L1 vocabulary outcomes. We also examined whether children acquired translational equivalents for words known in one language but not the other. Results indicated that children acquired translational equivalents, providing partial support for the transfer of vocabulary knowledge across languages.

Languages differ greatly in how they express causal events. In languages like Japanese, the subjects of causative sentences, or causers, are generally animate and intentional, whereas in other languages like English, causers range widely from animate beings to inanimate objects (e.g. Wolff, Jeon & Li, 2009). This paper explores when children learn to represent cause in their native tongue and how this learning occurs over the course of development. English- and Japanese-speaking preschoolers watched animations that were caused by (i) humans acting intentionally, (ii) humans acting accidentally, (iii) objects that generate energy (e.g. a machine), and (iv) objects that do not generate energy (e.g. a tool). Children were then asked to choose a good description of the event between two options. At age three, English- and Japanese-speaking children performed the task in similar ways, attending only to the intention of causal agents; however, at age four, speakers of the two languages diverged. English speakers were more likely to accept energy-generating objects such as machines as the subject of a lexical causative sentence than Japanese speakers.

The purpose of this study was to examine attention allocation in toddlers who were late talkers and toddlers with typical language development while they were engaged in a word-learning task in order to determine if differences exist. Two-year-olds who were late talkers (11) and typically developing toddlers (11) were taught twelve novel pseudo-words for unfamiliar objects over ten training sessions. The toddlers' attention allocation during the word-learning sessions was measured as well as their comprehension of the newly learned words. Late talkers showed reduced attention allocation to objects during word-training sessions, and also comprehended fewer of the novel words than toddlers with typical language development. Attention allocation was found to be a stronger predictor of word learning as compared to cognition and auditory comprehension. Reduced attention allocation may contribute to the early lexical delay characteristic in late talkers.

We report here on a series of elicited production experiments that investigate the production of indirect object and oblique relative clauses by monolingual child learners of English and Korean. Taken together, the results from the two languages point toward a pair of robust asymmetries: children manifest a preference for subject relative clauses over indirect object relative clauses, and for direct object relative clauses over oblique relative clauses. We consider various possible explanations for these preferences, of which the most promising seems to involve the requirement that the referent of the head noun be easily construed as what the relative clause is about.

This study investigated how forty-six mothers modified their talk about familiar and unfamiliar nouns and verbs when interacting with their children with Down Syndrome (DS), language impairment (LI), or typical development (TD). Children (MLUs < 2·7) were group-matched on expressive vocabulary size. Mother–child dyads were recorded playing with toy animals (noun task) and action boxes (verb task). Mothers of children with DS used shorter utterances and more verb labels in salient positions than the other two groups. All mothers produced unfamiliar target nouns in short utterances, in utterance-final position, and with the referent perceptually available. Mothers also talked more about familiar nouns and verbs and labelled them more often and more consistently. These findings suggest that mothers of children in the early period of language development fine-tune their input in ways that reflect their children's vocabulary knowledge, but do so differently for nouns and verbs.

The environmental context of verbs addressed by adults to young children is claimed to be uninformative regarding the verbs' meaning, yielding the Syntactic Bootstrapping Hypothesis that, for verb learning, full sentences are needed to demonstrate the semantic arguments of verbs. However, reanalysis of Gleitman's (1990) original data regarding input to a blind child revealed the context of single-word parental verbs to be more transparent than that of sentences. We tested the hypothesis that English-speaking children learn their early verbs from parents' single-word utterances. Distribution of single-word transitive verbs produced by a large sample of young children was strongly predicted by the relative token frequency of verbs in parental single-word utterances, but multiword sentences had no predictive value. Analysis of the interactive context showed that objects of verbs are retrievable by pragmatic inference, as is the meaning of the verbs. Single-word input appears optimal for learning an initial vocabulary of verbs.

The present study applies a multidimensional methodological approach to the study of the acquisition of morphosyntax. It focuses on evaluating the degree of productivity of an infrequent subject–verb agreement pattern in the early acquisition of French and considers the explanatory role played by factors such as input frequency, semantic transparency of the agreement markers, and perceptual factors in accounting for comprehension of agreement in number (singular vs. plural) in an experimental setting. Results on a pointing task involving pseudo-verbs demonstrate significant comprehension of both singular and plural agreement in children aged 2;6. The experimental results are shown not to reflect input frequency, input marker reliability on its own, or lexically driven knowledge. We conclude that toddlers have knowledge of subject–verb agreement at age 2;6 which is abstract and productive despite its paucity in the input.

Both the input directed to the child, and the child's ability to process that input, are likely to impact the child's language acquisition. We explore how these factors inter-relate by tracking the relationships among: (a) lexical properties of maternal child-directed speech to prelinguistic (7-month-old) infants (N = 121); (b) these infants' abilities to segment lexical targets from conversational child-directed utterances in an experimental paradigm; and (c) the children's vocabulary outcomes at age 2;0. Both repetitiveness in maternal input and the child's speech segmentation skills at age 0;7 predicted language outcomes at 2;0; moreover, while these factors were somewhat inter-related, they each had independent effects on toddler vocabulary skill, and there was no interaction between the two.

Young children are slow to master conventional intonation patterns in their yes/no questions, which may stem from imperfect understanding of the links between terminal pitch contours and pragmatic intentions. In Experiment 1, five- to ten-year-old children and adults were required to judge utterances as questions or statements on the basis of intonation alone. Children eight years of age or younger performed above chance levels but less accurately than adult listeners. To ascertain whether the verbal content of utterances interfered with young children's attention to the relevant acoustic cues, low-pass filtered versions of the same utterances were presented to children and adults in Experiment 2. Low-pass filtering reduced performance comparably for all age groups, perhaps because such filtering reduced the salience of critical pitch cues. Young children's difficulty in differentiating declarative questions from statements is not attributable to basic perceptual difficulties but rather to absent or unstable intonation categories.